Switch control device and method for power

ABSTRACT

A switch control device includes a switch device and a control device. The switch device includes first and second input terminals, an output terminal, a processor, and a plurality of delays. The processor is configured to detect period of an input voltage from the first input terminal, and to determine whether the input voltage is normal. A delay time can be computed by the processor, according to the period of the input voltage and a release time of the each delay. If the input voltage from the first input terminal is abnormal, the processor detects a zero voltage crossing signal or a peak of voltage signal, and delays the zero voltage crossover signal or the peak of voltage signal for a delay time, to control the delays coupled to the first input terminal to turn on.

FIELD

The subject matter herein generally relates to a switch control deviceand method for power.

BACKGROUND

A double input power source or a single input power source usuallysupplies power to an output through a switch device. The switch deviceusually may include a first relay, a second relay, and a siliconcontrolled rectifier (SCR) coupled to the first relay in parallel.However, the switch device will be damaged due to the SCR operating butnot until the second relay is turned on.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures.

FIG. 1 is a block diagram of an embodiment of an switch control devicecoupled to a first power source, a second power source, and anelectronic device.

FIG. 2 is a block diagram of a first embodiment of the switch controldevice of FIG. 1.

FIG. 3 is a circuit diagram of the first embodiment of the switchcontrol device of FIG. 1, wherein the switch control device may receivean input voltage, and comprise at least one relay.

FIG. 4 is a waveform schematic diagram of the input voltage relating toa first zero crossover signal of the input voltage, which to determine adelay time of the relay of the first embodiment of the switch controldevice of FIG. 1.

FIG. 5 is a waveform schematic diagram of the input voltage relating toa second zero crossover signal of the input voltage, which to determinea time of the relay of the first embodiment of the switch control deviceof FIG. 1.

FIG. 6 is a waveform schematic diagram of the input voltage relating toa third zero crossover signal of the input voltage, which to determine atime of the relay of the first embodiment of the switch control deviceof FIG. 1.

FIG. 7 is a schematic diagram of a second embodiment of the switchcontrol device.

FIG. 8 is a waveform schematic diagram of the input voltage relating toa first peak of wave signal of the input voltage, which to determine adelay time of the relay of the second embodiment of the switch controldevice of FIG. 7.

FIG. 9 is a waveform schematic diagram of the input voltage relating toa first peak of wave signal of the input voltage, which to determine adelay time of the relay of the second embodiment of the switch controldevice of FIG. 7.

FIG. 10 is a waveform schematic diagram of the input voltage relating toa first peak of wave signal of the input voltage, which to determine adelay time of the relay of the second embodiment of the switch controldevice of FIG. 7.

FIG. 11 is a flow chart diagram of the switch control device.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures and components have notbeen described in detail so as not to obscure the related relevantfeature being described. Also, the description is not to be consideredas limiting the scope of the embodiments described herein. The drawingsare not necessarily to scale and the proportions of certain parts havebeen exaggerated to better illustrate details and features of thepresent disclosure.

Several definitions that apply throughout this disclosure will now bepresented.

The term “coupled” is defined as connected, whether directly orindirectly through intervening components, and is not necessarilylimited to physical connections. The connection can be such that theobjects are permanently coupled or releasably coupled. The term“comprising,” when utilized, means “including, but not necessarilylimited to”; it specifically indicates open-ended inclusion ormembership in the so-described combination, group, series and the like.

The disclosure will now be described in relation to an electronic devicewith a switch control device for power.

FIG. 1 illustrates a schematic diagram of an embodiment of an switchcontrol device 100 coupled to a first power source 300, a second powersource 400, and an electronic device 200. The switch control device 100is configured to switch between the first power source 300 and thesecond power source 400, to supply voltage from the first power source300 or the second power source 400 to the electronic device 200.

FIG. 2 illustrates a block diagram of a first embodiment of the switchcontrol device 100 of FIG. 1. The switch control device 100 includes aswitch device 10 and a control device 20. In at least one embodiment,the switch device 10 is an automatic transfer switch. The switch device10 includes a first input terminal 11, a second input terminal 12, afirst switch unit 13, a second switch unit 14, and an output terminal15. The first input terminal 11 and the second input terminal 12 arecoupled to the first power source 300 and the second power source 400respectively. The output terminal 15 receives a first input voltage fromthe first power source 300 through the first input terminal 11, orreceives a second input voltage from the second power source 400 throughthe second input terminal 12. The control device 20 includes a detectionunit 23 and a processor 25. The detection unit 23 includes a voltagesensor 230 and a zero crossover signal sensor 231. The voltage sensor230 includes a first voltage sensor 2301 and a second voltage sensor2302. The zero crossover signal sensor 231 includes a first zerocrossover signal sensor 2310 and a second zero crossover signal sensor2312. The first zero crossover signal sensor 2310 and a second zerocrossover signal sensor 2311 and the first zero crossover signal sensor2310 are coupled to the first input terminal 11 and the processor 25.The second voltage sensor 2302 and the second zero crossover signalsensor 2311 are coupled to the second input terminal 12 and theprocessor 25. The processor 25 are coupled to the first switch unit 13and the second switch unit 14.

FIG. 3 illustrates a circuit diagram of the first embodiment of theswitch control device 100 of FIG. 1. Both of the first input terminal 11and the second input terminal 12 are coupled to the a municipal electricpower. The first switch unit 13 includes first level relay unit and asecond level relay unit. The first level relay unit of the first switchunit 13 includes relays R1 and R2. The second level relay unit of thefirst switch unit 13 includes relays R3 and R4, and two siliconcontrolled rectifiers (SCRs) S1 and S2. The two SCRs S1 and S2 arecoupled to the relays R3 and R4 in parallel. The second switch unit 14includes first level relay unit and a second level relay unit. The firstlevel relay unit of the second switch unit 14 includes relays R5 and R6.The second level relay unit of the second switch unit 14 includes relaysR7 and R8, and two silicon controlled rectifiers (SCRs) S3 and S4. Thetwo SCRs S3 and S4 are coupled to the relays R7 and R8 in parallel. Therelays R1 and R2 are coupled in series, and are coupled between a livewire L1 of the municipal electric power and the output terminal 15. Therelays R3 and R4 are coupled in series, and are coupled between aneutral wire N1 of the municipal electric power and the output terminal15. Each of the SCR is composed of two single thyristors coupled inparallel. A first terminal of the SCR S1 is coupled to a node betweenthe relay R1 and the relay R2. A second terminal of the SCR S1 iscoupled to the output terminal 15. A second terminal of the SCR S2 iscoupled to a node between the relay R3 and the relay R4. A secondterminal of the SCR S2 is coupled to the output terminal 15. The relaysR5 and R6 are coupled in series, and are coupled between a live wire L2of the municipal electric power and the output terminal 15. The relaysR7 and R8 are coupled in series, and are coupled between a neutral wireN2 of the municipal electric power and the output terminal 15. A firstterminal of the SCR S3 is coupled to a node between the relays R5 andR6. A second terminal of the SCR S3 is coupled to the output terminal15. A first terminal of the SCR S4 is coupled to the node between therelays R7 and R8. A second terminal of the SCR S4 is coupled to theoutput terminal 15.

The processor 25 includes a control chip 250, a relay driver 251, and aSCR driver 252. Each of the relays R1, R2, R3, R4, R5, R6, R7, and R8 iscoupled to the processor 25 through the relay driver 251. Each controlterminal of the SCR S1, S2, S3, and S4 is coupled to the processor 25through the SCR driver 252. The relay driver 251 and the SCR driver 252can make functions as adjusting voltages of the relays R1, R2, R3, R4,R5, R6, R7, and R8 and the SCR S1, S2, S3, and S4.

In at least one embodiment, the SCR S1 and S2 can promote a transmissiontime from the first input terminal 11 to the output terminal 15. The SCRS3 and S4 can promote a transmission time from the second input terminal12 to the output terminal 15. Each of the SCR can reduce a voltage dropof the corresponding relay coupled in parallel. Therefore, arc dischargegenerated by the relays R2, R4, R6, R8 can be reduced.

In use, when the output terminal 15 receives a first input voltage fromthe first input terminal 11, the first voltage sensor 2301 senses thefirst input voltage, and transmits the first input voltage to theprocessor 25. The first zero crossover signal sensor 2310 senses a zerocrossover signal of the first input voltage, and transmits the zerocrossover signal of the first input voltage to the processor 25. Theprocessor 25 detects a period T of the first input voltage through thefirst voltage sensor 2301, and determines whether the first inputvoltage is normal or not. If the first input voltage is abnormal, theprocessor 25 computes a delay time T_(Delay) according to the period Tof the first input voltage and a charge time T_(Operate) of relays R1and R3 of the first level relay unit of the first switch unit 13, anddetermines when to output a control signal to turn on the relays R1 andR3 of the first switch unit 13 according to the delay time T_(Delay) andthe zero crossover signal of the first input voltage. Therefore, avoltage generated by the operation of turn on the relays R1 and R3instantly will be reduce.

Each relay usually includes a coil and a plurality of contacts. In atleast one embodiment, the charge time T_(Operate) is a period startedfrom the coil of one relay receiving a turn on signal until the contactsof the relay contacting to each other, and the delay time T_(Delay) is aperiod between the processor 25 detects the zero crossover signal (ZCD)of the first input voltage and outputs control signal to the relays, tomake the relays to disconnect.

FIGS. 4 to 6 illustrates waveform schematic diagrams of the first inputvoltage relating to three forms of zero crossover signal (ZCD) of thefirst input voltage, which make the processor 25 to determine when tooutput the delay time T_(Delay) of each relay (Delay) of the firstswitch unit 13. In at least one embodiment, a relationship between theT_(Delay) and the T_(Operate) as formula: T_(Delay)=T−T_(Operate).

Therefore, the processor 25 detects the zero crossover signal (ZCD) ofthe first input voltage and outputs the control signal to the relays R1and R3 of the first switch unit 13 after the delay time T_(Delay), tomake the relays R1 and R3 operating. When the contacts of the relays R1and R3 of the first switch unit 13 coupled to the first input terminal11 turn on, and then the relays R2 and R4 will be turned on after a fewtime. Therefore, a voltage generated by the operation of turn on therelays R1 and R3 instantly will be reduce, which will avoid the SCRs S1and S2 are turned on not until the relays R2 and R4 are operating.

In at least one embodiment, the zero crossover signal of the first inputvoltage is a signal of the sinusoidal wave of the first input voltageapproach to an abscissa axis.

FIG. 7 illustrates a schematic diagram of a second embodiment of theswitch control device 100. Difference from the first embodiment of theswitch control device 100 is that, the detection unit 23 includes thevoltage sensor 230 and a peak of wave signal sensor 233. The peak ofwave signal sensor 233 includes a first peak of wave signal sensor 2330and a second peak of wave signal sensor 2331. The first peak of wavesignal sensor 2330 and the second peak of wave signal sensor 2331 areconfigured to receive the first input voltage and the second inputvoltage respectively, and detects peak of wave signal of the first orsecond input voltage, to transmit the peak of wave signal of the firstor second input voltage to the processor 25.

In at least one embodiment, operation principle of the switch controldevice 100 in the first embodiment is similar as that of the secondembodiment. When the output terminal 15 receives a first input voltagefrom the first input terminal currently, the first voltage sensor 2301detects the first input voltage from the first input terminal 11, andtransmits the first voltage to the processor 25. The first peak of wavesignal sensor 2330 detects the peak of wave signal of the first inputvoltage, and outputs the peak of wave signal to the processor 25. Theprocessor 25 detects the period T of the first input voltage through thefirst voltage sensor 2301, and determines whether the first inputvoltage is normal or not. If the first input voltage is abnormal, theprocessor 25 computes a delay time T_(Delay) according to the period Tof the first input voltage and the charge time T_(Operate) of each relayof the first switch unit 13, and determines when to output a controlsignal to turn on the relays R1 and R3 of the first switch unit 13according to the delay time T_(Delay) and the peak of wave signal of thefirst input voltage.

FIGS. 8 to 10 illustrates waveform schematic diagrams of the first inputvoltage relating to three forms of peak of wave signal (PKD) of thefirst input voltage, which make the processor 25 to determine when tooutput the delay time T_(Delay) of relays R1 and R3 (Delay) of the firstswitch unit 13. In at least one embodiment, a relationship between theT_(Delay) and the T_(Operate) as formula: T_(Delay) 3T/4−T_(Operate).

Therefore, the processor 25 detects the peak of wave signal (PKD) of thefirst input voltage and outputs the control signal to the relays R1 andR3 of the first switch unit 13 after the delay time T_(Delay). When thecontacts of the relays R1 and R3 of the first switch unit 13 coupled tothe first input terminal 11 are turned on, and then the relays R2 and R4will be turned on after a few time. Therefore, a voltage generated bythe operation of turn on the relays R1 and R3 instantly will be reduce,which will avoid the SCRs S1 and S2 are turned on not until the relaysR2 and R4 are operating.

Referring to FIG. 11, a flowchart is presented in accordance with anexample embodiment of a switch control device 100 which is being thusillustrated. The example method is provided by way of example, as thereare a variety of ways to carry out the method. The method describedbelow can be carried out using the configurations illustrated in FIGS.1, 2,3, and 7. The exemplary method can be executed by an switch controldevice 100, and can begin at block 1101.

At block 1101, the voltage sensor 230 receives the first input voltagefrom the first input terminal.

At block 1102, a sensor, such as the zero crossover signal sensor 231 orthe peak of wave signal sensor 233 senses the zero crossover signal orthe peak of wave signal of the first input voltage.

At block 1103, the processor 25 receives the first input voltage fromthe voltage sensor 230.

At block 1104, the processor 25 detects the period T of the first inputvoltage.

At block 1105, the processor 25 determines whether the first inputvoltage is normal or not, If the first input voltage is abnormal, theprocess goes to block 1105, otherwise, the process goes to block 1101.

At block 1106, the processor 25 computes a delay time T_(Delay)according to the period T of the first input voltage and the charge timeT_(Operate) of the relay of the first switch unit 13.

At block 1107, the processor 25 determines when to output a controlsignal to turn on the relays R1 and R2 of the first switch unit 13according to the delay time T_(Delay) and the zero crossover or peak ofwave signal of the first input voltage.

When the second input terminal 12 transmits the second input voltagefrom the second source S2 to the output terminal 15 through the secondswitch unit 14, and the second voltage sensor 2302 operates, theprinciple is similar to the first input terminal 11 transmits the firstinput voltage from the first source S1 to the output terminal 15 throughthe first switch unit 13, and the first voltage sensor 2301 operates.

While the disclosure has been described by way of example and in termsof the embodiment, it is to be understood that the disclosure is notlimited thereto. On the contrary, it is intended to cover variousmodifications and similar arrangements as would be apparent to thoseskilled in the art. Therefore, the range of the appended claims shouldbe accorded the broadest interpretation so as to encompass all suchmodifications and similar arrangements.

What is claimed is:
 1. A switch control device comprising: at least oneinput terminal; at least one switch device comprising at least one inputterminal, at least one switch unit coupled to a corresponding one of theat least one input terminal, and an output terminal, wherein each of theat least one switch unit comprising a first relay unit, a second relayunit, and a silicon controlled rectifier (SCR) coupled to the secondrelay unit in parallel; a control device comprising: a detection unitcoupled to the at least one input terminal and configured to detect azero crossover signal of an input voltage from the at least one inputterminal; a processor coupled to the detection unit and at least oneswitch unit, wherein the processor is configured to: receive the inputvoltage and the zero crossover signal of the input voltage; detect aperiod of the input voltage, and determine whether the input voltage isnormal or not; wherein when the first input terminal from the firstinput terminal is abnormal, the processor computes a delay timeaccording to the period of the input voltage and a charge time of relaysof one switch unit coupled to one input terminal from at least one inputterminal and controls the relays to turn on according to the delay timeand the zero crossover signal of the first zero crossover signal of theinput voltage.
 2. The switch control device of claim 1, wherein switchdevice comprising a first input terminal, a second input terminal, afirst switch unit, and a second switch unit, the first and second switchunit are coupled to the first and second input terminal respectively;the output is configured to receive a first input voltage from the firstinput terminal through the first switch unit, or to receive a secondinput voltage from the second input terminal through the second switchunit; the detection unit is coupled to the first and second inputterminals, and is configured to detect a zero crossover signal of thefirst or second input voltage; the processor is configured to detect aperiod of the first or second input voltage, and detect whether thefirst or second input voltage is normal; when the processor detect thefirst input voltage is abnormal, the processor computes the delay timeaccording to the period of the first input voltage and the charge timeof relays of the first switch unit, and controls the relays to turn onaccording to the delay time and the zero crossover signal of the firstzero crossover signal of the input voltage.
 3. The switch control deviceof claim 2, wherein the detection unit comprises a voltage sensor and azero crossover signal sensor, both of the voltage sensor and the zerocrossover signal sensor are coupled to the first input terminal, thesecond input terminal, and the processor, the voltage sensor isconfigured to receive the first or second input voltage, and to transmitthe first or second input voltage to the processor.
 4. The switchcontrol device of claim 3, wherein the zero crossover signal sensorcomprises a first zero crossover signal sensor and a second zerocrossover signal sensor, the first zero crossover signal sensor and thesecond zero crossover signal sensor are coupled to the first inputterminal and the second input terminal respectively, the processor isconfigured to detect the zero crossover signal of the first inputvoltage through the first zero crossover signal sensor, or to detect thezero crossover signal of the second input voltage through the secondzero crossover signal sensor.
 5. The switch control device of claim 4,wherein the voltage sensor comprises a first voltage sensor and a secondvoltage sensor, the first voltage sensor and the second voltage sensorare coupled to the first input terminal and the second input terminalrespectively, the processor is configured to detect whether the periodof the first input voltage is normal or not through the first voltagesensor, or to detect whether the period of the second input voltage isnormal or not through the second voltage sensor.
 6. The switch controldevice of claim 1, wherein each of the switch unit further comprisesthird and fourth relays, a first silicon controlled rectifier (SCR), andsecond SCR; the first and second relays are coupled in series, and arecoupled between a live wire of the first or second input terminal andthe output terminal; the third and fourth relays are coupled in series,and are coupled between a neutral wire of the first or second inputterminal and the output terminal; a first terminal of the first SCR iscoupled to a node between the first relay and the second relay, a secondterminal of the first SCR is coupled to the output terminal; a firstterminal of the second SCR is coupled to a node between the third relayand the fourth relay, a second terminal of the second SCR is coupled tothe output terminal; controls terminal of the each SCR is coupled to theprocessor, each of the relays is coupled to the processor.
 7. A switchcontrol device comprising: at least one input terminal; at least oneswitch device comprising at least one input terminal, at least oneswitch unit coupled to a corresponding one of the at least one inputterminal, and an output terminal, wherein each of the at least oneswitch unit comprising a first relay unit, a second relay unit, and asilicon controlled rectifier (SCR) coupled to the second relay unit inparallel; a control device comprising: a detection unit coupled to theat least one input terminal, and configured to detect a peak of wavesignal of an input voltage from the at least one input terminal; aprocessor coupled to the detection unit and at least one switch unit,wherein the processor is configured to: receive the input voltage andthe peak of wave signal of the input voltage; detect a period of theinput voltage, and determine whether the input voltage is normal or not;wherein when the first input terminal from the first input terminal isabnormal, the processor computes a delay time according to the period ofthe input voltage and a charge time of relays of one switch unit coupledto one input terminal from at least one input terminal, and controls therelays to turn on according to the delay time and the peak of wavesignal of the first peak of wave signal of the input voltage.
 8. Theswitch control device of claim 7, wherein switch device comprising afirst input terminal, a second input terminal, a first switch unit, anda second switch unit, the first and second switch unit are coupled tothe first and second input terminal respectively; the output isconfigured to receive a first input voltage from the first inputterminal through the first switch unit, or to receive a second inputvoltage from the second input terminal through the second switch unit;the detection unit is coupled to the first and second input terminals,and is configured to detect a peak of wave signal of the first or secondinput voltage; the processor is configured to detect a period of thefirst or second input voltage, and detect whether the first or secondinput voltage is normal; when the processor detect the first inputvoltage is abnormal, the processor computes the delay time according tothe period of the first input voltage and the charge time of relays ofthe first switch unit, and controls the relays to turn on according tothe delay time and the peak of wave signal of the first peak of wavesignal of the input voltage.
 9. The switch control device of claim 8,wherein the detection unit comprises a voltage sensor and a peak of wavesignal sensor, both of the voltage sensor and the peak of wave signalsensor are coupled to the first input terminal, the second inputterminal, and the processor, the voltage sensor is configured to receivethe first or second input voltage, and to transmit the first or secondinput voltage to the processor.
 10. The switch control device of claim9, wherein the peak of wave signal sensor comprises a first peak of wavesignal sensor and a second peak of wave signal sensor, the first peak ofwave signal sensor and the second peak of wave signal sensor are coupledto the first input terminal and the second input terminal respectively,the processor is configured to detect the peak of wave signal of thefirst input voltage through the first peak of wave signal sensor, or todetect the peak of wave signal of the second input voltage through thesecond peak of wave signal sensor.
 11. The switch control device ofclaim 10, wherein the voltage sensor comprises a first voltage sensorand a second voltage sensor, the first voltage sensor and the secondvoltage sensor are coupled to the first input terminal and the secondinput terminal respectively, the processor is configured to detectwhether the period of the first input voltage is normal or not throughthe first voltage sensor, or to detect whether the period of the secondinput voltage is normal or not through the second voltage sensor. 12.The switch control device of claim 11, wherein each of the switch unitfurther comprises third and fourth relays, a first silicon controlledrectifier (SCR), and second SCR; the first and second relays are coupledin series, and are coupled between a live wire of the first or secondinput terminal and the output terminal; the third and fourth relays arecoupled in series, and are coupled between a neutral wire of the firstor second input terminal and the output terminal; a first terminal ofthe first SCR is coupled to a node between the first relay and thesecond relay, a second terminal of the first SCR is coupled to theoutput terminal; a first terminal of the second SCR is coupled to a nodebetween the third relay and the fourth relay, a second terminal of thesecond SCR is coupled to the output terminal; controls terminal of theeach SCR is coupled to the processor, each of the relays is coupled tothe processor.
 13. A control method of a switch control devicecomprising: a voltage sensor receiving an input voltage from an inputterminal; a signal sensor sensing a zero crossover signal or the peak ofwave signal of the input voltage; a processor receiving the inputvoltage and detecting the period of the input voltage, and determiningwhether the input voltage is normal or not, the processor computing adelay time according to the period of the input voltage and a dischargetime of relay of a first switch unit when the input voltage is abnormal;the processor determining when to output a control signal to turn off ofthe relays of the first switch unit, according to the delay time and thezero crossover signal or the peak of wave signal of the input voltage.